Hey Mike, while following the time course experiments vignette, I continue to get an error when I use the code below: 

fiss <- plotCounts(ddsTC, which.min(resTC$padj), 
                   intgroup = c("minute","strain"), returnData = TRUE)
ggplot(fiss,
  aes(x = as.numeric(minute), y = count, color = strain, group = strain)) + 
  geom_point() + geom_smooth(se = FALSE, method = "loess") + scale_y_log10()

The error says: Error: could not find function "geom_point"

I intend to plot gene expression changes over time between wild type and knockout mice. This is a follow-up from yesterday's post. Thanks for your help.

Can you please post your

sessionInfo()

output? Because an improperly attached ggplot2 would be the most obvious reason. In case you copy and pasted above code you might also want to check, whether there is an irrgeular newline between )) +  and geom_point(), which could cause the trouble, too.